Lan extension

i have a controller that have two VLAN:1) VlAN 1 (MANAGEMENT address).2) VlAN 20 (for this vlan the controller doesn't have an address)

The controller have two interfaces linked to a switch, fa1/7 (in access on VLAN 20)and fa1/6 (in accesso on VLAN 1).

I want to propagate by a RAP the VLAN 20, and if i connect to rap's SSID, the controller links me to the switch in Layer 2.So is like if i am directly connected to my LAN without routing, and i recive an ip by my external dhcp, and the controller works like a L2 switch.